The present invention relates to a head slider supporting mechanism for a magnetic disk apparatus.
A head slider supporting mechanism installed in a magnetic disk apparatus includes a suspension which holds a head slider and a head arm to which the suspension is mounted. The suspension has to be flexible in order to urge the head slider against the surface of a rigid or a flexible rotating magnetic disk by an adequate load and to allow the head slider to follow the changing topography of disk surface.
To meet the above requirement, a conventional head slider supporting mechanism is provided with a suspension element which is mounted on a rigid arm block, as disclosed in U.S. Pat. No. 4,167,765. The suspension element includes a load beam section having flanges at both sides thereof and a resilient spring section adapted to provide the load beam section with resiliency. A gimbal spring is welded to the tip of the suspension element in order to hold a head slider. The gimbal spring includes two flexible outer fingers which are parallel to each other in the longitudinal direction of the suspension element and a center tongue to which the head slider is fastened by adhesive. The center tongue is provided with a semispherical protuberance at its intermediate portion and free at one of its opposite ends. The head slider is fastened to the center tongue of the gimbal spring such that the longitudinal direction of floating surfaces of two side rails of the head slider are perpendicular to the longitudinal axis of the suspension element, i.e. that of the gimbal spring.
The head slider is required to roll about its longitudinal axis and to pitch about an axis which is perpendicular to the longitudinal axis so as to follow the surface of the magnetic disk. In the conventional head slider supporting mechanism, however, it is difficult to enable the head slider to follow the circumferential changing topography of the disk surface with high accuracy. This is because while the rigidity of the head slider in the longitudinal direction (rolling direction) is as low as 30 gf-mm/rad, the rigidity in the direction perpendicular to the longitudinal direction (pitching direction) is as high as 65 gf-mm/rad which is more than double the former.
In another conventional head slider supporting mechanism, the longitudinal axis of the suspension element, i.e., that of the gimbal spring and the longitudinal axis of the head slider are substantially aligned with each other as described in U.S. Pat. No. 4,620,251. This kind of mechanism suffers from a drawback that, contrary to the first-mentioned conventional mechanism, the rigidity in the rolling direction is far greater than the rigidity in the pitching direction, preventing the head slider from accurately following radial changing topography of the disk surface.
U.S. Pat. No. 4,486,798 teaches a head slider supporting mechanism in which the head slider is located with its longitudinal axis angled by 4 degrees to 10 degrees relative to the axis which is perpendicular to the longitudinal axis of the suspension element. In this structure, the head slider is provided with a certain skew angle relative to all concentric tracks which are provided on the magnetic disk so that damage (head crash) to an electromagnetic transducer of the head slider, the suspension element and the disk surface due to dust may be reduced. Even in such a mechanism, the rigidity in the rolling direction is far greater than that in the pitching direction and, hence, the head slider fails to follow the changing topography of the disk surface with high accuracy.